Change of physical and thermal decomposition properties of in situ heavy oil with steam temperature

Ikiztepe crude oil was subjected to four different steam temperatures during steam injection which was applied as an enhanced oil recovery process on a linear limestone model saturated with oil. Produced oils were characterized using density, viscosity measurements, pyrolysis experiments utilizing TGA and elemental analysis runs. Results showed that produced crude oils change in measured characteristics as compared to the original oil. These changes include an increase in H/C, and cracking activation energy, decrease in density, viscosity and amount of residue remaining after cracking (coke). Also, decrease in asphaltene amount, changes in the elemental composition of asphaltenes and increase in the cracking activation energies were observed at 225 degrees C run. These measurements show that the produced oils get lighter and differ compositionally from the original oil as steam temperature increases. Decrease in elemental sulphur amount is one of the major changes when environmental considerations are concerned. Residual oil left in the limestone pack on the other hand shows an increase in the low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO) activation energies as determined from TGA combustion experiments on the samples taken from the pack after steam injection experiments

Adsorption and gas transport in coal microstructure: investigation and evaluation by quantitative X-ray CT imaging

Natural gas (methane) production from coal seams is recognized as one of the valuable energy sources due to high storage capacity of coal to store gas at low pressures. It is known that coal composition, pore structure, and mineral matter properties affect both the amount of adsorbed quantity and kinetics of adsorption when the coals are considered for natural gas production or mediums for storing gas, mainly methane or carbon dioxide

Fracture/cleat analysis of coals from Zonguldak Basin (northwestern Turkey) relative to the potential of coalbed methane production

In this study, the fracture structure of three coals (Sulu K-1, Acihk K-2 and Cay Dogu Ayak) from two different seams in the Zonguldak Basin located on the Black Sea coast of Turkey have been analyzed in relation to coalbed methane recovery. X-ray computerized tomography (CT), light microscopy image analysis and scanning electron microscopy (SEM) analysis have been performed on mine coal samples to have a better understanding of distribution of minerals, fracture morphology and apertures and matrix/fracture interactions via examination of fracture surfaces

Assessment of energetic heterogeneity of coals for gas adsorption and its effect on mixture predictions for coalbed methane studies

This study explains the single-component and binary mixture adsorption studies on two different coals from the Zonguldak Basin (Northwestern Turkey). Assessment of energetic heterogeneity of coal surface and its effect on the equilibrium binary gas adsorption are discussed. Single component adsorption tests were performed using methane and carbon dioxide at 30 degreesC. Binary mixtures prepared with 10, 15 and 20% carbon dioxide were also tested at the same temperature. Various single-component adsorption isotherms were fitted to the experimental data of single gases. The data obtained from these models were interpreted to determine the energetic heterogeneity of the coals towards adsorption of methane and carbon dioxide. Ideal adsorbed solution (IAS) theory was used to predict the data and discrepancies between experimental data, and the model predictions were interpreted. Results showed that coals exhibit a heterogeneous behavior in gas adsorption. This heterogeneity can be different for each coal-gas pair and the extent of the heterogeneity makes the binary gas predictions differ from the experimental data. The deviations between IAS and experimental data increase as the amount of gas, to which the coal shows high heterogeneity, increases in the mixture

Behavior and effect of SARA fractions of oil during combustion

In this study, saturate, aromatic, resin, and asphaltene fractions of two Turkish crude oils (medium and heavy) were separated by column chromatographic techniques. Combustion experiments were performed on whole oils and fractions by a thermogravimetric analyzer (TG/DTG) and differential scanning calorimeter (DSC) by using air and a 10 degrees C/min heating rate. TG and DSC data were analyzed for the determination of weight loss due to possible reactions, and for reaction enthalpies of individual fractions, which have to be known for in-situ combustion technology utilization